What features will it include?

It also details facial recognition technology that acts both as an ID system and maps users' expressions onto animated emoji characters known as Animoji.

Rumoured animoji to be coming to new iPhone

Three models

Apple is rumoured to be working on three versions of its next iPhone - 4.7-inch and 5.5-inch models, which will essentially be upgraded versions of the iPhone 7 and 7 Plus, and a new 5.8-inch model, which will be Apple's special edition iPhone X.

While the 5.8-inch iPhone X sounds like it would be massive, Apple is reportedly working on a new edge-to-edge display technology, so although the screen area would be bigger, the phone itself could actually be smaller than the iPhone 7 Plus.

OLED display

In March 2016, Nikkei reported that Apple was planning to ditch LCD displays in favour of OLED screens, with the first OLED iPhone arriving in 2017.

Then in April 2017, DigiTimes reported that Apple had signed a two-year deal with Samsung to supply the OLED panels.

OLED displays are superior to the LCD panels currently used in Apple’s iPhones because, rather than requiring a backlight, an OLED-based screen lights up individual pixels when necessary.

No Home button

Rumours have been swirling for some time that Apple is planning to get rid of the traditional physical Home button and replace it with a touch-sensitive digital button.

A Chinese website called Storm reports that the virtual home button will have the same haptic feedback motors used in the iPhone 7 to create the illusion of a Home button, even if it's really just a flat capacitive surface.

Apple iPhones

The biggest challenge appears to be integrating the Touch ID sensor into the display, with some rumours suggesting Apple will get around the problem by moving the fingerprint reader to the back of the phone.

The patent suggests Apple will use acoustic imaging technology to record a fingerprint.

The technology doesn't need an optical image of your finger. Instead an acoustic transducer under the glass sends so-called 'piezoelectric signals' through the phone when it detects impact. These signals trigger waves sent through the screen.

The returning waves scan the tiny ridges and valleys of your fingerprint to work out if it's actually you or not. Each fingerprint has a unique acoustic pattern that would then allow you access to the phone.

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Camera

The iPhone X is expected to feature the same dual-lens rear camera featured on the iPhone 7 Plus. Given that Apple only unveiled its dual-lens technology in 2016, it is unlikely to make any major changes to it in 2017.

However, Ming-Chi Kuo thinks that Apple's next iPhone could come with a "revolutionary" new selfie camera that uses infrared technology to detect the location and depth of objects in its field of vision.

The 3D camera system could be used for facial recognition, iris recognition and 3D selfies. It could also be used in augmented reality mobile games, to accurately replace a character's head with that of the user, Kuo wrote in a research report seen by 9to5mac.

The 3D system works by sending invisible infrared light signals outwards from the phone and then detecting the signals that bounce back off of objects using the 1.4 megapixel infrared receiver.

Kuo said that, in the future, Apple could add 3D sensing technology to its rear cameras as well, removing the need for large dual camera iris systems.

Wireless charging

Wireless charging has become a common feature of some Android smartphones - including Samsung's latest family of devices - although it is still a lot slower than wired charging methods.

Face ID

One of the stand-out features of Samsung 's latest flagship smartphone, the Galaxy S8, is facial recognition technology, allowing users to unlock their phone by simply looking at it.

Now eagle-eyed software engineers have found evidence that the same feature could be included in the iPhone X, by scouring through the code for the HomePod speaker - Apple's answer to the Amazon Echo or Google Home, due to be launched in December 2017.

As the speaker needs to work seamlessly with Apple's new phones, the firmware code contains references to some upcoming features that Apple fans can expect to see.

Revealed on Twitter by developer Steve Troughton-Smith it appears the next iPhone will include an infrared camera that could be used to scan your face, even in the dark.

It's likely this technology will be included so users can unlock the phone just by looking at it - in a similar way to Samsung's Galaxy S8 smartphone.

An Apple iPhone 6s - details of the latest Apple device called the "iPhone X" have been revealed in an apparent leak. (Image: Lauren Hurley/PA Wire)

When will it be released?

Apple is holding an event today at its newly built headquarters in Cupertino, California, where it is widely expected to unveil the iPhone X.

That means the new phone is likely to be available for pre-order from Friday, September 15, and could hit the shelves as soon as September 22. Apple traditionally releases its latest iPhones during the first two weeks of September, in good time for the start of the Christmas shopping season.

This will be the first iPhone launch held at the company's massive new headquarters - the so-called "spaceship campus" . Tim Cook will take to the stage of the Steve Jobs Theatre - named after Apple's legendary co-founder.

The event is due to start at 10am Pacific Time, which translates to 6pm here in the UK. As ever, it is expected to be live streamed so thousands of eager Apple fans around the world can watch.

The price was reportedly leaked to The Fast Company by "a source with knowledge of Apple's plans". The source said that part of the reason for the high price tag is the OLED display, which will cost Apple roughly twice as much as the LCD display used in current iPhones.

The new phone is also likely to get a memory upgrade from the current iPhone 7 line, which will add to the cost of manufacturing the device.